Air-preheating device for stoves and furnaces



H. R. BRUNNER. AIR PREHEATING DEVICE FOR STOVES AND FURNACES.

I APPLICATION FILED DEC-31, 19I8. msmmg Patented M 31,1922.

3 SHEETS-SHEET I.

i l Illw w H. R. BRUNNER.

AIR PREHEATING DEVICE- FOR STOVES AND FURNACES. APPLICATION man Diem. l9l8.

1,433,601; Patented 00a 31,1922, (Q g 3SHEETSSHEET 3.

NS b & O I a I o OI'I W o f m P N 9 7 9 Elvwewioz Patented Get. 331, i922.

HERBERT R. BR'UNNER, OF NEW YORK, N. '55., ASSIGNOR, BY MESNE ASSIGNDIENT S, TO

VAN KANNEL REVOLVING DOOR COMPANY,

OF NEW JERSEY.

Avnlication filed December 31, 1918.

To all whom it mag concern:

Be it known that I, HERBERT R. BRUNNER, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Air-Preheating Devices for Stoves and Furnaces, of which the following is a specification.

This invention relates to improvements in air preheating devices for aiding combuse tion in furnaces and more particularly to such a device adapted for attachment to the furnace door, and to extend into the combu stion chamber.

The primary object of the invention is to deliver to the combustion zone, or the combustion chamber of a furnace, the proper amount of adequately preheated air, for all draft conditions, that is to say, without excessive air flow under high draft and with adequate air flow under minimum draft, and

to provide means for adequately preheating said air.

I am aware that many devices of this character have been devised in which the air is baffled in its passage through the preheater, but these have apparently. merely taken into consideration, the idea of retarding the flow of the air so as to give it time to become heated by contact with the very considerable amount of metallic heating surface formed by baffies variously shaped and variously arranged within the device; The element of time during which the air in passing through the'preheater, is exposed to the heating surface of the preheater, does not seem to have been taken into serious account, the result being that such devices amounted to nothing more than open passages leading from the outside to the inside of the furnace, virtually without control, and with no perceptible rise in temperature.

My experiments have demonstrated that the success of a device of this character depends upon the necessary control of the air through the preheater under varying draft conditions, and upon the volume, as tlHS.

must be substantial and upon supplying an adequate amount of heat to the air in passing through the device, to bring it to the proper temperature to be delivered into the furnace and that the control referred to as a practical proposition must be an automatic control, that is to say, a control that is in- OF NEW] YORK, N. L, A CORPORATION AIR-PREHEATING DEVICE FOR STOVES AND FURNACES.

Serial 1T0. 269,034.

herent in the device itself, so that it acts automatically to deliver a substantial and proper quantity of adequately preheated air.

In the construction about to be described, if amenabled to employ channels-of large cross sectional area, and consequentlylarge capacity, which, while having in commonthe feeding function of the air, are so prochannels having different characteristics,

which channels maybe termed primary and secondary heating channels, the second ary channels being the control element of the device. Between the various channels, both large and relatively small, I arrange for ninety and one hundred and eighty degree reversals of the air, by the provision of the transfer passages situated at the ends of the channels, wherethrough the air is transferred from one channel to the other, which is the control feature of the device.

By the reversals referred to retardation of air is introduced 'in my invention, and by the use of relatively large storage reservoirs or channels,eXposed to the heat in the furnace, the relatively slow moving mass of air is thoroughly and uniformly preheated and by the employement, in connection with these relatively large channels, of'a series or plurality of comparatively attenuated channels or channels of smaller cross sectional area, which are in communication with the reservoir channels, and with each other, through transfer openings arranged at the alternate, ends of the channels, by which the direction of flow of the air is sharply reversed, and thereby retarded, an automatic control is accomplished and the device rendered capable of delivering only the required and desired quantity of adequately preheated air under minimum draft, which amount will be increased under increase in draft, but will be held to the maximum requirements under maximum drafts. By the use of primary and secondary heating channels, the former being that or those I have referred to as storage or reservoir channels, with the sharp reversals between them, I am free to use relatively large channels for primary heating, which are large enough relative to the secondary channels, to supply the required air flow, with low velocity. The condition of air fiow in the large channel or channels being more nearly at a state of rest, the requisite condition for facilitating the heating of said air is greatly in' proved, as the slow moving mass of air willtake up heat more readily from the highly heated surfaces of the device than if it were carried forward at high speed, the comparative slowness of movement, giving the air an opportunity of intermingling and circulating in contact with the heated walls of the chambers or channels, It is necessary, in order to get good results, that all of the molecules of the air be brought successively into contact with the heated surface, for the reason that air is not a good conductor of heat if at all, and the molecules of the air must be heated by convection, hence the large channels or chambers, in which the air is maintained comparatively at a state of rest. Not only does the provision of large preheating or reservoir channels serve their purpose as storage chambers, but they present a large area of heating surface and consequently have the capacity for more highly heating the air brought in contact, with the surfaces,

In-the drawings illustrating the invention- Figure 1 is a side elevation of a portion of a furnace of ordinary construction, with the part adjacent the fire door broken away to show the preheater attached to the furnace door. I

Figure 2 is a vertical sectional view of the preheater taken about on line 22 of Figure 4:.

Figure 3 is a horizontal sectional view taken on'line"3-3 of Figure 2.

Figure 4: is a vertical longitudinal section of the heater, taken about on line 4t4: of

Figure 2, looking toward the front or in i take side of the casing, a d

Figure 5 is an enlarged perspectiv i partly broken away, designed to' show the entire internal construction of the device.

It will be understood at the outset'that the preheater 1s made of metal indifferent ber of the furnace, in position to deliver the adequately preheated air into the products of combustion from the fire bed. I

Referring to the drawings, A designates a furnace of any approved construction, B the fire door, the fire door damper, D the grate, and E the ash pit door.

The numeral 1 designates the preheater which is a metallic casing generally rectangular in shape, and of oblong contour, and is formed with a top plate 2, bottom plate 3, end plates 4 and 5, front plate 6, and rear plate 17, the plate 7 inclining inwardly as indicated at 8, and joining the bottom plate 3, so that the casing presents to the fire in the combustion chamber of the furnace, a beveled surface which deflects to some extent, the heat and prevents the burning or fusing of the metalfrom intense heats. The plates referred to are cast integral and at the bottom and top of the casing I provide ears providedwith apertures 10, for the passage of bolts 11,-by which the preheater is attached to the furnace door B, the form illustrated being one adapted for attachment to the door, rather than to form an integral part of the door casting.

As before suggested, the terms channels and ohambers may be usedinterchangeably, because while the vertical and horizontal partitions form, with the walls of the casing, channels, they also form chambers, and particularly is this true of the bottom channel 12, which is storage or reservoir chamber or channel, which is, relative to the other channels, of large cross sectional area and consequently of relatively lar 'e capacity. This channel has direct communication with the outside air, through the usual opening in the furnace door, through inlet opening 13 in the inset portion l l'of the frontplate 6 of the casing, which in set portion extends, asillustrated best in .Figure 4, for substantially the entire length of the preheater. thus forming, when the de vice is against the flat surface of the furnace door, a horizontal chamber for the lateral circulation of the air across the entire face of the preheater, in order that it reach the opening 18 from points encompassing the entire area of the damper arrangements of the furnace door.

The lower chamber 12, sometimes called a storage chamber, is formed-by horizontal partitions 15, vertical wall 6, rear wall 8,

bottom 3, and portions of end walls 4 and' Vertical chamber 17 is formed by a part of horizontal partition 18, vertical wall 16, part of end wall 5, and parts of vertical partition 20 and front wall 6. The partition 15 is provided with a transfer opening 15, through which communication is established between the 1 outside atmosphere and the reservoir or storage channel 12. lntermedt ate ofthe partltions 1 5 and 18 1s a horizon tal partition 19, which extends for about one half of the length of the casing, and is integral with the front wall of the casing and with a vertical partition 20 which e2;- tends from the top of the casing to the partition 15, this partition being, like the others, integral. with the walls of the casing. By this arrangement of vertical and horizontal partitions in, the front part of the casing, control channels 21, 22 and 23 are formed. The channel 21 is in communication with the reservoir or storage channel through trans for passage 24, and the channel 21. is in communication with the channel 22 by large transfer passage 25 and. the channel 22 is in communication with the top channel 23 through transfer passage 26, as clearly shown in Figure 4.

The partition as shown in Figure 2 extends entirely to the rear plate and with said plate, and a partition 27, forms a distributing channel 28 in communication with a similar channel through transfer passage 30, formed in the partition 27, and the rear of the casing opposite these two last mentioned channels is provided with a series of discharge openings -31; through which the adequately preheated air passes to and i'ningles with the products of combustion in the combustion chamber of the furnace, after it has been, by the draft conditions of the furnace, drawn from the lower storage or reservoir channel and passed vertically and horizontally through the parts of the casing above the large channel, being meanwhile subjected to sharp reversals and re tardation effects, the flow of the air being upon 90 and 180 reversals.

The vertical partition is provided near one end of the casino; with. a transfer pas- 29, through which communication. is

established between the channel 23 and the the chamber formed between the front wall of the casino; of the insideof the furnace door v and through the inlet opening 13, downwardly to the reservoir or storage channel 12, and passes with a comparatively slow movement, due to volume of air, for the entire length of the casing, through transfer opening 24:, into the channel .21, through transfer passage 25 to the channel 2.2. and through channel 22 to the top chan incl. 23, through transfer opening 26, and entirely across the too of the casing, and into the ront channel 29 through transfer opening 29' and is distributed throughout the length of the channel 29 to the opposite end of the casing, where it passes down wardly to the channel 28 through transfer passage 30, from which channels 29 and 28, the air passes in comparatively small. streams, through the discharge openings 31, where it mixes with the products of coinhustion the furnace. i Having thus described my invention, what I claim is: 11hr; air preheating device forpromotingrombustionf in furnaces and the like, comprising a casing provided at its bottom with. a storage channel of comparatively e cross sectional area, and having an air line-t communicating directly with the said channel, a plurality of vertical and horizontal partitions which, together with the walls of'the easing, form horizontal channels in communication with each other, and with the storage channel in series, through suitable transfer passages, and suitable discharge openings in the rear of the cas ng, through which air is discharged into the furnace after having passed back and forth through the various channels. I

2. An air preheating device for aiding combustion in furnaces and the like, having in the lower portion thereof a reservoir channel of comparatively large cross sectional. areaand capacity, and having a verijxicalpassage, and an inlet opening above the reservoir channel and communicating therewith through said vertical passage so that air flowing into the preheater will pass first into the reservoir or storage channel, a horizontal partition extending entirely across the casing and forming the top wall of the storage channel, and a vertical partition intersecting the horizontal partition and extending to the too of the casing, there being horizontal partitions intersecting the vertical partition. which form. with the walls ofthe casing, horizontal channels transfer passages arranged in the partitions, whereby communication in series between the channels is established, and suitable discharge openings in; the rear of the casing through which air, after it has passed through the channels is introduced into the combustion chamber of the furnace.

A. preheating device for aiding combustion in furnaces and the like, comprising a casing having therein a horizontal partition extending entirely across the casing, thus, with the walls of the casing. forming a storage chamber, an air inlet in the front of the casing having directcommunication with the storage chamber, a vertical partition intersecting the horizontal partition and extendinn: to the top plate of the easinn; and for the full length of the casing, a horizontal partition intersecting the rear of the casing and the vertical partition, thus dividing the back part of the easing into two horizontal channels, horizontal parti- CII upper rear channel, and a transfer passage in the rear horizontal partition, whereby communication is established between the two rear channels, and suitable discharge openings in the rear wall of the casing through which air-is discharged from the rear channels.

HERBERT R. BRUNNER.

lVitnesses ,TITIAN 3V. Jot-INsoN,

FRANK G, Bnnnnrozcr 

